4. Modbus RTU
4 - 6
4.8 Function Codes
4.8.1 List of function codes
The MR-JE-_C servo amplifier supports the following function codes.
Code
Function name
Description
Broadcast communication
03h
Read Holding Registers
Reading data in holding registers
The data in the registered holding registers can be read from the
master.
Not supported
08h
Diagnostics
Function diagnostics
When this function code is sent from the master to a slave, the
slave returns the received data to the master without any
changes.
Communication checks can be performed.
Not supported
10h
Preset Multiple Registers
Writing data in multiple holding registers
Continuous multiple data sets can be written in the registered
holding registers from the master.
Supported
4.8.2 Read Holding Registers (Reading data in holding registers: 03h)
Data in consecutive registers is read for the specified number of data points starting from the specified
register address.
(1) Message frame
Query Message
Slave Address
Function
Starting Address
No. of Points
CRC Check
H
L
H
L
L
H
(8 bits)
03h
(8 bits)
(8 bits)
(8 bits)
(8 bits)
(8 bits)
(8 bits)
Message
Size
Description
Slave Address
8 bits
Set a station number to which the message is sent.
The number "0" (station number for broadcast sending) cannot be set.
Function
8 bits
Set "03h".
Starting Address (Note)
16 bits
Set a start address of the holding registers to read.
No. of Points
16 bits
Set the number of points of data to read starting from the start address of the
holding registers from which data is read.
Set the number of read points described in the list of holding registers.
To read the data in continuous registers, set a value obtained by adding the
number of read points of the target registers to this number.
CRC Check
16 bits
Data for CRC error check
This data is calculated automatically by a controller.
Note. Registers can be classified into two types: registers that can be continuously accessed and particular registers that cannot be
continuously accessed.
To read particular registers, read only the target registers.
For the details on whether the target registers can be continuously accessed or not, refer to the directions for use of each function
of the Modbus registers described in chapter 7.
Summary of Contents for MR-JE-C Series
Page 9: ...A 8 MEMO ...
Page 13: ...4 MEMO ...
Page 33: ...2 CC Link IE Field Network Basic SLMP 2 16 MEMO ...
Page 73: ...5 PARAMETERS 5 14 MEMO ...
Page 79: ...6 MANUFACTURER FUNCTIONS 6 6 MEMO ...
Page 143: ...MEMO ...
